The invention concerns a saddle support for securing a saddle of a vehicle, typically of a bicycle; said saddle support comprising an outer part that surrounds at least a portion of an inner part with formation of a gap, which inner part receives the saddle, a rolling bearing for a linear mounting of the inner part on the outer part being arranged in the gap, and the support further comprising a spring element acting in mounting direction for spring-mounting the inner part.
With a view to improving comfort, bicycles having spring-mounted and cushioned saddles are being offered for sale for some time past. Shocks introduced into the bicycle frame due to unevenness of the roadway are thus not transmitted directly into the saddle but are rather mitigated and damped. A saddle support known from DE 201 02 011 U1, for example, comprises an inner tube and an outer tube both having an annular cross section. The outer diameter of the inner tube is smaller than the inner diameter of the outer tube. The outer tube surrounds a portion of the inner tube with formation of an annular gap. Balls arranged in the gap enable a relative linear motion between the inner and the outer tube. It is also possible to use rollers or other rolling elements in place of the balls. The balls are guided with the help of raceway plates that are inserted into the inner or the outer tube and comprise cavities extending in an axial direction. Two raceway plates are arranged at an offset of 160xc2x0 to each other on the inner peripheral surface of the outer tube, so that the inner tube is perfectly mounted linearly on the outer tube. A drawback of this prior art rolling bearing is that only a limited length of travel is possible The limit of travel is reached when the balls or other rolling elements reach the end of the raceway plates. A further drawback is to be seen in the fact that due to vibrations during operation and under the action of gravity, the balls slip gradually downwards so that a satisfactory displacement is no longer guaranteed.
It is an object of the invention to provide an improved saddle support of the pre-cited type which guarantees a perfect mounting of the inner part on the outer part.
This and other objects and advantages of the invention will become obvious from the following detailed description.
The invention achieves the above objects by the fact that the rolling bearing is a linear bearing assembly with recirculation of rolling elements which are in rolling contact with rolling element raceways, at least one of said rolling element raceways being configured on the linear bearing assembly and at least one other of said rolling element raceways being configured on the inner part. An important advantage of the saddle support of the invention is that a theoretically unlimited length of travel is possible. Linear bearing assemblies with recirculation of rolling elements have been known, per se, for a long time. Due to their compact structure, and in conjunction with necessary modifications to the inner tube and the outer tube, they can make a substantial contribution to enhancing comfort For example, with the saddle support of the invention it is possible without any problem, to use springs with differently dimensioned spring excursions without having to match the spring excursion to the maximum travel length of the rolling bearing. Besides this, no measures are required on the outer part for configuring a rolling element raceway because a raceway is already provided on the linear bearing assembly.
The preferably tubular outer part may comprise a reception in which the linear bearing assembly is fixed. The reception can be formed, for instance by making a step in the tubular outer part and delimiting this step at an inner axial end by a shoulder. The linear bearing assembly can then be pressed, for example, into the reception without any problem till it comes to abut against the shoulder and thus reaches its final position.
The inner part may be constituted by a tube having a smooth, cylindrical outer peripheral surface which then directly forms the rolling element raceway. In this case, so-called recirculating linear ball bearings are particularly suited as linear bearing assemblies that enable a return of the rolling elements because such recirculating linear ball bearings are likewise suitable for torque transmission even if, as is the case here, the shaft has a smooth, cylindrical outer peripheral surface. The rolling elements in the present embodiment are balls that are in rolling contact with the cylindrical outer peripheral surface. In another embodiment of the invention, ball grooves are made in an axial direction in the cylindrical outer peripheral surface of the inner part and the balls are in rolling contact with these ball grooves. In this embodiment a perfect transmission of torque is guaranteed due to the configuration of the raceway as a ball groove In this case, too, recirculating linear ball bearings are particularly suited.
Such recirculating linear ball bearings preferably comprise an outer bushing that can be pressed into the initially mentioned reception of the outer part. The saddle support of the invention can therefore be manufactured in a very simple manner. To keep a momental loading about an axis perpendicular to the longitudinal axis as low as possible in the linear bearing assembly with recirculation of rolling elements, two linear bearing assemblies spaced apart in axial direction are provided in another embodiment of the invention.
The invention will now be described more closely with reference to two embodiments illustrated in the four appended drawings.